The Pentagon unveils $1.3 billion for Ukraine, bringing total new U.S. aid this week to $2.3 billion.

The United States will send $1.3 billion in financial assistance to Kyiv in order to purchase a host of new military equipment and ammunition, the Pentagon said on Wednesday. The new security support followed several U.S. announcements of humanitarian and other aid, and brought the total new U.S. commitment to Ukraine this week alone to $2.3 billion.

The United States has invested more in Ukraine’s defense and recovery than any other country, according to a tracker compiled by the Keil Institute in Germany. That data shows that total U.S. aid to Ukraine since shortly before the war had surpassed $70 billion by the end of May, including military support, humanitarian aid and financial commitments.

The new funds announced by the Pentagon will buy four additional air-defense missile systems called NASAMS, which are jointly produced by the United States and Norway; more 152-millimeter artillery shells for Ukraine’s older Soviet-era howitzers; anti-tank missiles and one-way attack drones; as well as equipment for clearing land mines.

Fighting through Russian anti-tank and anti-personnel land mines are a major obstacle for Ukrainian forces pressing their slow-moving counteroffensive, leading to many casualties. Gen. Mark A. Milley, the chairman of the Joint Chiefs of Staff, addressed that problem on Tuesday following a virtual meeting of the Ukraine Defense Contact Group — a coalition of about 50 nations that meets monthly to discuss military and humanitarian aid for Kyiv, which includes all NATO countries as well as many of the United States’ non-NATO allies.

“The casualties that the Ukrainians are suffering on this offensive are not so much from Russian air power. They’re from minefields,” General Milley said, noting that Russian troops with antitank weapons were poised to engage Ukrainian forces trying to cross mined areas. “So the problem to solve is minefields.”

During the briefing, the general pushed back on the idea that Ukraine’s counteroffensive, which began in early June, was faltering.

“It’s a tough fight. It’s a very difficult fight,” General Milley said. “It started about five or six weeks ago, and the various war games that were done ahead of time had predicted certain levels of advance, and that has slowed down. Why? Because that’s the difference between war on paper and real war. These are real people in real machines that are out there really clearing real minefields, and they’re really dying.”

General Milley said that the Pentagon had already provided Ukrainian forces with explosive charges specifically designed to clear paths through those minefields and would continue to do so.

The drones Ukraine will buy, called Phoenix Ghost and Switchblade, are light enough to be carried by soldiers in the field. Once launched, they are flown via remote control and can surveil a target before crashing into it and exploding on impact.

The funds will also purchase a number of vehicles, secure communication equipment and devices for countering Russian drones and electronic jamming equipment.

The Pentagon’s announcement of the new aid package came during a week in which the United States also announced successive humanitarian, agricultural and economical aid packages through its Agency for International Development, or U.S.A.I.D., that totaled about $1 billion.

The leader of the agency, Samantha Power, said on Monday during a visit to Kyiv that the U.S. would send $500 million to help fund food, medical and shelter assistance for people affected by the war. On Tuesday, a day after Russia refused to extend the Black Sea grain deal, U.S.A.I.D. announced $250 million in aid to support Ukrainian farmers. And on Wednesday, the agency announced an additional $230 million to help Ukraine’s economy recover from the war.

Anushka Patil contributed reporting.